Took SP 20 from Castiadas, then the left turn at the summit of the SP 20 pass. The roads are very well maintained - you could drive up with any average car. The slope is not too bad, but consistent for a long distance. Right at the end there are some steeper areas that are hard to climb. At the summit the last few hundred meters of the trail are cemented, but extremely steep as well. The view is amazing and worth it!